| 摘要 |
<p>A public-key encryption system. Encryption of a k -bit plaintext m is performed by picking a random x ˆˆ Z N * , generating ciphertext c = y m x 2k mod N, and outputting the ciphertext. N is a non-prime integer (preferably the product of two primes p and q ), y is an element in multiplicative group Z N * of integers modulo N , and k is an integer larger than 1. Decryption of ciphertext c using private key is performed by recovering m ˆˆ {0,..., 2 k - 1} such that y p 2 k m = c p 2 k mod p holds and outputting plaintext m , wherein ( a p �¢ ) 2 k denotes the 2 k -th power residue symbol modulo p , which is defined as ( a p �¢ ) 2 k = a p - 1 2 k �¢ mod p . Also provided are an encryption device (100) and a decryption device (100). The encryption scheme provides better bandwidth than the Goldwasser-Micali encryption scheme.</p> |
